Hours later, police said they had shot dead "four suspected terrorists" and left another injured in Cambrils, a city south of Barcelona.

The regional government of Catalonia, where both Barcelona and Cambrils are located, also confirmed the incident in the early hours of Friday, which police had earlier qualified as a "possible terrorist attack."

Here is everything we know.

What happened in Barcelona?

A white Fiat van, reportedly rented, rammed into pedestrians outside a kosher restaurant on a busy street in Barcelona shortly after 5pm on Thursday.

The vehicle van veered onto the promenade and barreled down the busy walkway in central Barcelona for 500 metres, swerving back and forth as it mowed pedestrians down and turned a picturesque tourist destination into a bloody killing zone.

Victims were left sprawled in the street, spattered with blood or writhing in pain from broken limbs. Others fled in panic through Las Ramblas, screaming or carrying young children in their arms.

Lawyer and University of Glasgow rector Aamer Anwar was walking La Ramblas when he heard screaming.

He said a shopkeeper told him five or six people were badly injured and described the scene as "chaos".

Mr Anwar said: "I was walking down Las Ramblas for something to eat. Part of it was in the shade so I decided to keep walking down and literally within 10 seconds there was a crashing noise.

"I turned around and people were screaming - I could see a woman screaming with her kids - people started running and jumping into shops. I ran for about 50 or 100 metres and stopped to see what was happening. "

British tourist Keith Welling, who arrived in Barcelona on Wednesday with his wife and 9-year-old daughter, said they saw the van drive past them down the avenue and took refuge in a restaurant when panic broke out and the crowd started running.

"People were shouting and we heard a bang and someone cried that it was a gunshot ... Me and my family ran into the restaurant along with around 40 other people.

"At first people were going crazy in there, lots of people crying, including a little girl around three years old."

What happened in Cambrils?

Residents of the Spanish seaside resort of Cambrils fled in terror in the early hours of Friday after five terrorists wearing suicide vests launched the second ramming attack in the country in a matter of hours.

At least six people were hurt when the attackers drove into pedestrians before being shot dead by security forces, just hours after a similar attack in nearby Barcelona.

Of the six civilians caught up in the Cambrils attack, two were said to be in a serious condition.

The Audi A3 car rammed into people on the seaside promenade of the tourist city 74 miles south of Barcelona, where a van had earlier sped into a street packed full of tourists, killing 13 people and injuring around 100 others.

Police said the suspects in Cambrils carried bomb belts, which were detonated by a police bomb squad.

Media reports said a car crashed into a police vehicle and nearby civilians and police shot the attackers, one brandishing a knife. Police did not immediately say how the attack was being carried out.

A police officer and five civilians were injured and two were in serious condition.

The explosive belts worn by attackers killed by police in Cambrils were fake, the Spanish region's head Carles Puigdemont told local radio station RAC1. He said bomb experts had confirmed the explosive belts were duds.

The suspects

Four people have so far been arrested over the attack, including Driss Oukabir, the elder brother of van driver suspect Moussa Oukabir.

The driver of the van that mowed into the packed street was still on the run, Spanish police said on Thursday night.

There was a third arrest made on Friday morning - but it was unclear whether this was the driver.

Josep Lluis Trapero of the regional police of Catalonia said two other people suspected of being involved in the terror attack had been arrested - a Spaniard and a Moroccan.

One of the suspects arrested over the attack is a man born in the Spanish territory of Melilla in northern Morocco, he said.

The other, Driss Oukabir, is Moroccan.

A handout photo made available by Spanish National Police shows Maghrebi Driss Oukabir, alleged to have rented the van which was used to crashed into pedestrians in Las RamblasCredit:
Spanish National Police/ HANDOUT

Neither of them had any criminal record, he added.

Spanish reports initially said that Driss Oukabir was being questioned on suspicion of involvement in the attack.

But on Thursday night the mayor of Ripoll, the town where he lived, 70 miles north of Barcelona, said that a man identifying himself as Driss Oukabir went to his local police station and reported that his documentation had been stolen.

Jordi Munell, the mayor, said that the man had insisted that he had been in Ripoll at the time of the attack and went to the local police station as soon as he saw his images broadcast in the media.

In a further twist, Trapero said police suspected a deadly explosion late on Wednesday at a house in Alcanar 124 miles south of Barcelona was linked to the van attack.

Trapero said the explosion left at least one person dead, and police suspected those in the house were "preparing an explosive device."

"It seems there was an accumulation of gas that generated the explosion," he said, without giving further details.

The Spanish suspect was arrested in Alcanar, while Oukabir was held in Ripoll in northern Catalonia.

Isil claim responsibility

"Soldiers" of Islamic State of Iraq and the Levant carried out the deadly van attack, the jihadist organisation's propaganda outlet Amaq said.

"The executors of the Barcelona attack were soldiers of the Islamic State," Amaq said on its Telegram messenger account, without naming those it claimed were behind the attack.

Amaq said they had launched the attack in response to calls to target states taking part in the United States-led coalition battling the jihadist group in Iraq and Syria.

Spanish Prime Minister Mariano Rajoy said the attack was "jihadist terrorism" which required a global response.

"Today the fight against terrorism is the principal priority for free and open societies like ours. It is a global threat and the response has to be global," Rajoy told a news conference in Barcelona.

Isil, which once controlled a self-declared "caliphate" across large parts of Iraq and Syria, has suffered major losses in recent months. Coalition-backed Iraqi forces recaptured its Iraqi stronghold Mosul in July.

World leaders condemn perpetrators and offer support to Spain

Prime Minister Theresa May said she is "sickened by the senseless loss of life in Barcelona".

"My thoughts are with the victims of today's terrible attack in Barcelona and the emergency services responding to this ongoing incident," she said. "The UK stands with Spain against terror.

"Following the attacks in Manchester and London, Spain stood alongside the British people. Tonight, Britain stands with Spain against the evil of terrorism."

U.S. President Donald Trump wrote on Twitter: "The United States condemns the terror attack in Barcelona, Spain, and will do whatever is necessary to help. Be tough & strong, we love you!"

The United States condemns the terror attack in Barcelona, Spain, and will do whatever is necessary to help. Be tough & strong, we love you!

In Germany, the office of German Chancellor Angela Merkel said they were thinking of the victims of the "revolting attack" with "profound sadness", while French President Emmanuel Macron voiced "France's solidarity" with Spanish citizens following what he called "a tragic attack".

Russian President Vladimir Putin called for the world to unite in an "uncompromising battle against the forces of terror".

"We decisively condemn this cruel and cynical crime against civilians," Putin wrote in a telegram of condolences to Spanish King Felipe VI.

The missing, dead and injured

The family of a seven-year-old boy has posted on Facebook begging for his safe return after he was separated from his injured mother.

Julian Cadman, from Australia, was out in Barcelona on holiday with his mother, when the terrorist's van struck where they were walking, separating them.

Julian is missingCredit:
Jom Cadman

Jom Cadman, the mother of Julian, was found in hospital and is in a serious but stable condition.

His cousin, George Cadman, wrote on Facebook: "My cousin, Julian Alessandro Cadman is missing. Please like and share. We have found Jom (his Mum, my cousin-in-law) and she is in a serious but stable condition in hospital.

"Julian is 7 years old and was out with Jom when they were separated, due to the recent terrorist activity. Please share, especially if you have family or friends in Barcelona. Thank you."

Victims of the van rampage that left 14 people dead and around 100 others injured were of at least 24 different nationalities, Spain's civil protection agency said.

A three-year-old child is among those confirmed dead, Spanish media reported, while authorities said a Belgian woman also died.

Spanish media also reported that three Germans were among those killed.

In Australia, Foreign Affairs Minister Julie Bishop confirmed that four Australians had been hurt in the attack, while one person was missing.

A spokesman had earlier said that among the victims in the popular seaside city were nationals from France, Germany, Spain, the Netherlands, Argentina, Venezuela, Belgium, Australia, Hungary, Peru, Romania, Ireland, Greece, Cuba, Macedonia, China, Italy and Algeria - without detailing whether he was referring to those who died or were injured.

Witnesses spoke of a scene of carnage, with bodies strewn along the boulevard as others fleeing for their lives.

"When it happened I ran out and saw the damage," local shop worker Xavi Perez told AFP.

"There were bodies on the floor with people crowding round them. People were crying. There were lots of foreigners."